Method of designing and manufacturing low-profile customized patient-specific orthopaedic surgical instruments

ABSTRACT

Methods of designing and manufacturing a number of low-profile metallic customized, patient-specific orthopaedic surgical instruments are disclosed.

CROSS-REFERENCE

Cross-reference is made to U.S. patent application Ser. No. 15/878,715,entitled “LOW-PROFILE CUSTOMIZED PATIENT-SPECIFIC ORTHOPAEDIC SURGICALINSTRUMENTS,” and U.S. patent application Ser. No. 15/878,710, entitled“CUSTOMIZED PATIENT-SPECIFIC ANTERIOR-POSTERIOR CHAMFER BLOCK ANDMETHOD,” which were filed concurrently with this application and areexpressly incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgicalinstruments and, more particularly, to customized patient-specificorthopaedic surgical instruments.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.For example, in a total knee arthroplasty surgical procedure, apatient's natural knee joint is partially or totally replaced by aprosthetic knee joint or knee prosthesis. A typical knee prosthesisincludes a tibial tray, a femoral component, and a polymer insert orbearing positioned between the tibial tray and the femoral component. Ina hip replacement surgical procedure, a patient's natural acetabulum isreplaced by a prosthetic cup and a patient's natural femoral head ispartially or totally replaced by a prosthetic stem and femoral ball.

To facilitate the replacement of the natural joint with a prosthesis,orthopaedic surgeons use a variety of orthopaedic surgical instrumentssuch as, for example, cutting blocks, drill guides, milling guides, andother surgical instruments. Typically, the orthopaedic surgicalinstruments are reusable and generic with respect to the patient suchthat the same orthopaedic surgical instrument may be used on a number ofdifferent patients during similar orthopaedic surgical procedures.

The orthopaedic surgical instruments may also be customized to aspecific patient. Such “customized patient-specific orthopaedic surgicalinstruments” are single-use surgical tools for use by a surgeon inperforming an orthopaedic surgical procedure that is intended, andconfigured, for use on a particular patient. It should be appreciatedthat these instruments are distinct from standard, non-patient specificorthopaedic surgical instruments that are intended for use on a varietyof different patients. These customized patient-specific orthopaedicsurgical instruments are distinct from orthopaedic prostheses, whetherpatient-specific or generic, which are surgically implanted in the bodyof the patient. Rather, customized patient-specific orthopaedic surgicalinstruments are used by an orthopaedic surgeon to assist in theimplantation of orthopaedic prostheses.

SUMMARY

According to one aspect of the disclosure, a method of manufacturing acustomized patient-specific orthopaedic surgical instrument isdisclosed. The method comprises generating a three-dimensional model ofa patient's bone based on patient-specific data, identifying a firstregion of the three-dimensional model of the patient's bone, defining anouter boundary of a customized patient-specific surgical instrument onthe three-dimensional model of the patient's bone, generating acustomized patient-specific surgical instrument model within the outerboundary, the customized patient-specific surgical instrument modelcomprising a bone-facing surface including a customized patient-specificnegative contour that receives a corresponding positive contour of thepatient's bone, and fabricating the customized patient-specificorthopaedic surgical instrument from metallic material based on thecustomized patient-specific surgical instrument model. The step ofgenerating the customized patient-specific surgical instrument modelcomprises defining a cavity in the bone-facing surface over the firstregion of the three-dimensional model of the patient's bone. The cavityhas an outer edge that is aligned with or larger than the outer edge ofthe first region. The step of generating the customized patient-specificsurgical instrument model also comprises generating an outer surface ofthe customized patient-specific surgical instrument opposite thebone-facing surface, extending a guide body outward from the outersurface of the customized patient-specific surgical instrument model toa free end, and defining a guide slot in the guide body, the guide slotbeing sized and shaped to guide a surgical tool into engagement with thepatient's bone.

In some embodiments, method may also comprise identifying a plannedresection plane on the three-dimensional model of the patient's bonebased on the patient-specific data. The step of defining the guide slotthrough the guide body may include aligning the guide slot with theplanned resection plane, and sizing and shaping the guide slot to guidethe cutting saw blade along the planned resection plane into engagementwith the patient's bone.

Additionally, in some embodiments, the step of sizing and shaping theguide slot includes defining the guide slot between a medial sidewalland a lateral sidewall of the guide body, and at least one of the medialsidewall and the lateral sidewall are angled relative to the other ofthe medial sidewall and the lateral sidewall.

In some embodiments, the guide slot may be a first guide slot, andgenerating the customized patient-specific surgical instrument model mayfurther comprise extending a boss outward from the outer surface of thecustomized patient-specific surgical instrument model to a free end thatis spaced apart from the free end of the guide body and defining a drillguide slot in the boss. In some embodiments, the step of extending theboss outward from the outer surface may include defining a taperedsurface on a first side of the boss, and fabricating the customizedpatient-specific orthopaedic surgical instrument from metallic materialincludes layering metallic material in a fabrication machine such thatthe tapered surface faces downward in the fabrication machine.

In some embodiments, the step of generating the customizedpatient-specific surgical instrument model may further comprise defininga plurality of apertures that extend through the outer surface and thebone-facing surface.

In some embodiments, the step of generating the customizedpatient-specific surgical instrument model may further comprise defininga second plurality of apertures through the guide body of the customizedpatient-specific surgical instrument model. Additionally, in someembodiments, n each of the apertures may include a diamond-shapedopening.

In some embodiments, the step of extending the guide body outward fromthe outer surface of the customized patient-specific surgical instrumentmodel to the free end may include defining a tapered surface on a firstside of the guide body, and fabricating the customized patient-specificorthopaedic surgical instrument from metallic material may includelayering metallic material in a fabrication machine such that thetapered surface faces downward in the fabrication machine.

In some embodiments, the step of fabricating the customizedpatient-specific orthopaedic surgical instrument from metallic materialbased on the customized patient-specific surgical instrument model mayinclude forming the customized patient-specific orthopaedic surgicalinstrument as a single monolithic component.

In some embodiments, the single monolithic component may include aplurality of laminations of metallic material.

According to another aspect, a method of manufacturing a customizedpatient-specific orthopaedic surgical instrument comprises generating athree-dimensional model of a patient's bone based on patient-specificdata, defining an outer boundary of a customized patient-specificsurgical instrument on the three-dimensional model of the patient'sbone, generating a customized patient-specific surgical instrument modelwithin the outer boundary, the customized patient-specific surgicalinstrument model including a customized patient-specific bone facingsurface, and fabricating the customized patient-specific orthopaedicsurgical instrument from metallic material based on the customizedpatient-specific surgical instrument model. The step of generating thecustomized patient-specific surgical instrument model comprisesgenerating an outer surface of the customized patient-specific surgicalinstrument opposite the bone-facing surface, extending a guide bodyoutward from the outer surface of the customized patient-specificsurgical instrument model to a free end, and defining a guide slot inthe guide body. The guide slot may be sized and shaped to guide asurgical tool into engagement with the patient's bone.

In some embodiments, the method may include planning a resected surfaceof the patient's bone, and generating the customized patient-specificsurgical instrument model may include shaping an outer edge of thebone-facing surface to match an outer edge of the planned resectedsurface of the patient's bone.

In some embodiments, the guide body may be a first guide body, andgenerating the customized patient-specific surgical instrument modelfurther may comprise extending a second guide body outward from theouter surface of the customized patient-specific surgical instrumentmodel to an end spaced apart from the free end of the first guide body,defining a second guide slot in the second guide body, the second guideslot being sized and shaped to guide a surgical tool into engagementwith the patient's bone and extending transverse to the first guideslot.

In some embodiments, the step of generating the customizedpatient-specific surgical instrument model may further compriseextending a third guide body outward from the outer surface of thecustomized patient-specific surgical instrument model to a free endspaced apart from the first guide body, and defining a third guide slotthe second guide slot being sized and shaped to guide a surgical toolinto engagement with the patient's bone and intersecting the secondcutting guide slot.

Additionally, in some embodiments, the second guide body may include aboss having a tapered outer surface, and the second guide slot may be adrill guide slot sized and shaped to guide a surgical drill intoengagement with the patient's bone.

In some embodiments, the step of fabricating the customizedpatient-specific orthopaedic surgical instrument from metallic materialbased on the customized patient-specific surgical instrument model mayinclude forming the customized patient-specific orthopaedic surgicalinstrument as a single monolithic component.

In some embodiments, the step of fabricating the customizedpatient-specific orthopaedic surgical instrument may include operating athree-dimensional metal printer to fabricate the customizedpatient-specific surgical instrument by forming laminations of metallicmaterial.

According to another aspect, a method of designing a customizedpatient-specific orthopaedic surgical instrument comprises generating athree-dimensional model of a patient's bone based on patient-specificdata, defining an outer boundary of a customized patient-specificsurgical instrument on the three-dimensional model of the patient'sbone, and generating a customized patient-specific surgical instrumentmodel within the outer boundary. The customized patient-specificsurgical instrument model includes a customized patient-specific bonefacing surface. In some embodiments, generating the customizedpatient-specific surgical instrument model comprises generating an outersurface of the customized patient-specific surgical instrument oppositethe bone-facing surface, extending a guide body outward from the outersurface of the customized patient-specific surgical instrument model toa free end, and defining a guide slot in the guide body, the guide slotbeing sized and shaped to guide a surgical tool into engagement with thepatient's bone.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a perspective view of a customized patient-specificorthopaedic femoral cutting block;

FIG. 2 is a posterior side elevation view of the cutting block of FIG.1;

FIG. 3 is an anterior side elevation view of the cutting block of FIG.1;

FIG. 4 is a proximal plan view of the cutting block of FIG. 1;

FIG. 5 is a distal plan view of the cutting block of FIG. 1;

FIG. 6 is a side elevation view of the cutting block of FIG. 1 shownpositioned relative to a distal end of a patient's femur;

FIG. 7 is another side elevation view of the cutting block of FIG. 1shown positioned relative to the distal end of the patient's femur;

FIG. 8 is a cross-sectional elevation view taken along the line 8-8 inFIG. 3;

FIG. 9 is a side elevation view of a guide pin body of the cutting blockof FIG. 1;

FIG. 10 is a distal plan view of the guide pin body of FIG. 9;

FIGS. 11A-B illustrate a simplified flow diagram of a process ofdesigning and fabricating the cutting block of FIG. 1;

FIGS. 12-15 illustrate some of the steps of the process outlined inFIGS. 11A-B;

FIG. 16 is a perspective view of a customized patient-specificorthopaedic tibial cutting block;

FIG. 17 is a posterior side elevation view of the cutting block of FIG.16;

FIG. 18 is an anterior side elevation view of the cutting block of FIG.16;

FIG. 19 is a distal plan view of the cutting block of FIG. 16;

FIG. 20 is a proximal plan view of the cutting block of FIG. 16;

FIG. 21 is a side elevation view of the cutting block of FIG. 16;

FIG. 22 is another side elevation view of the cutting block of FIG. 16;

FIG. 23 is a perspective view of a customized patient-specificorthopaedic femoral cutting guide;

FIG. 24 is a distal plan view of the femoral cutting guide of FIG. 23;

FIG. 25 is a proximal plan view of the femoral cutting guide of FIG. 23;

FIG. 26 is a side elevation view of the femoral cutting guide of FIG.23;

FIG. 27 is a cross-sectional elevation view taken along the line 27-27and FIG. 24;

FIG. 28 is a perspective view of the femoral cutting guide of FIG. 23aligned with a resected distal end of the patient's femur;

FIG. 29 is an elevation view showing that the femoral cutting guide ofFIG. 23 is sized and shaped to match the resected distal end of thepatient's femur;

FIG. 30 is a perspective view of the femoral cutting guide of FIG. 23positioned on the resected distal end of the patient's femur;

FIGS. 31-37 are views of another embodiment of a customizedpatient-specific femoral cutting block;

FIG. 38 is a perspective view of another embodiment of a customizedpatient-specific femoral cutting block;

FIG. 39 of another embodiment of a customized patient-specific femoralcutting block; and

FIGS. 40-41 are perspective views of another embodiment of a customizedpatient-specific femoral cutting block.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to effect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Referring to FIGS. 1-10, a customized patient-specific orthopaedicsurgical instrument 10 is shown. What is meant herein by the term“customized patient-specific orthopaedic surgical instrument” is asurgical tool for use by a surgeon in performing an orthopaedic surgicalprocedure that is intended, and configured, for use on a particularpatient. As such, it should be appreciated that, as used herein, theterm “customized patient-specific orthopaedic surgical instrument” isdistinct from standard, non-patient specific orthopaedic surgicalinstruments (i.e., “patient-universal instruments” such aspatient-universal cutting blocks) that are intended for use on a varietyof different patients and were not fabricated or customized to anyparticular patient. Additionally, it should be appreciated that, as usedherein, the term “customized patient-specific orthopaedic surgicalinstrument” is distinct from orthopaedic prostheses or implants, whetherpatient-specific or generic, which are surgically implanted in the bodyof the patient. Rather, an orthopaedic surgeon uses customizedpatient-specific orthopaedic surgical instruments to assist in theimplantation of orthopaedic prostheses. Examples of “customizedpatient-specific orthopaedic surgical instruments” include customizedpatient-specific drill/pin guides, customized patient-specific tibialcutting blocks, customized patient-specific femoral cutting blocks, andcustomized patient-specific alignment guides. The surgical instrument 10shown in FIGS. 1-10 is one embodiment of a customized patient-specificfemoral cutting block including a cutting guide slot 12 positioned toguide a customized, patient-specific resection of a distal end 14 of apatient's femur 16 (see FIGS. 6-7) along a predetermined resectionplane. As described in greater detail below, the femoral cutting block10 is configured to be coupled to the patient's femur 16 in a uniquepre-determined location and orientation. In the illustrative embodiment,the structure of the cutting block 10 has been contoured to reduce itssize relative to conventional cutting blocks and avoid contact withundesirable regions of the patient's bone.

As shown in FIG. 1, the femoral cutting block 10 includes a base plate20 and a number of surgical tool guide bodies 22 that are attached to,and extend outwardly from, the base plate 20. In the illustrativeembodiment, the femoral cutting block 10 is a single monolithiccomponent formed from a metallic material such as, for example,stainless steel. In that way, the base plate 20 and the guide bodies 22form a single monolithic metallic block. As described in greater detailbelow, the femoral cutting block 10 is formed by Direct Metal LaserSintering (DMLS), also known as Selective Laser Sintering (SLS), whichis a form of 3-D printing technology. In DMLS, the femoral cutting block10 is formed in a layer-by-layer fashion using laser sintering in whichlight fuses metallic powder, forming the metallic structures that definethe femoral cutting block 10. It should be appreciated that other formsof 3-D printing technology such as, for example, optical fabrication,photo-solidification, or resin printing may be used to fabricate thefemoral cutting block 10.

The base plate 20 includes a pair of arms 24, 26 that are configured toengage the distal end 14 of the patient's femur 16. The arms 24, 26 arespaced apart from each other such that a notch 28 is defined between theinner edges of the arms 24, 26. The notch 28 is sized and shaped tocorrespond to the natural intercondylar notch 30 (see FIG. 12) of thepatient's femur 16, which is defined between the natural condyles 32, 34of the patient's femur. In that way, contact within bone surfaces withthe natural intercondylar notch 30, which may be difficult to model, isavoided.

As shown in FIGS. 1-4, each of the arms 24, 26 has a bone-contacting orbone-facing surface 36 that engages one of the natural condyles 32, 34.In the illustrative embodiment, each bone-facing surface 36 includes anumber of negative contours 38 that are configured to receive a portionof the natural condyles 32, 34. As shown in, for example, FIGS. 2, 4,and 6-8, each contour 38 has a unique set of ridges 40 and depressions42 that are shaped to engage a corresponding unique set of depressions44 and ridges 46 of the natural condyles 32, 34. Each of the arms 24, 26also includes an outer surface 48 that is positioned opposite itscorresponding bone-facing surface 36. In the illustrative embodiment,each outer surface 48 is substantially smooth. As used herein, the term“substantially” should be understood to refer to permit the normaltolerances created by manufacturing variation and other design criteria.As such, a “substantially smooth surface” is one that is smooth withinthe normal tolerances created or permitted by manufacturing variationand other design criteria.

As shown in FIG. 1, the base plate 20 also includes an anterior flange50 that is configured to engage the distal end 14 of the patient's femur16. The anterior flange 50 includes a bone-facing surface 52 thatincludes a number of negative contours 54 that are configured to receivea portion of the patient's femur 16. As shown in, for example, FIGS. 2,4, and 8, the contour 54 of the anterior flange 50 has a unique set ofridges 56 and depressions 58 that are shaped to engage a correspondingunique set of depressions 60 and ridges 62 of the patient's femur 16.The anterior flange 50 also includes an outer surface 64 that ispositioned opposite the bone-facing surface 52. In the illustrativeembodiment, the outer surface 64 is substantially smooth.

The negative contours 38, 54 of the base plate 20 permit the cuttingblock 10 (and hence the tool guide bodies) to be positioned on thepatient's femur 16 in a unique pre-determined location and orientation.As shown in FIGS. 4 and 6-8, the bone-facing surface 52 includes a pairof curved posterior edges 66, 68 that define a portion of the contour 54and are shaped to match a portion of the patient's femur. As a result,each of the edges 66, 68 includes convex and concave portions to receivecorresponding concave and convex portions of the patient's femur. Theedge 66 includes a posterior tip 69 that is sized and shaped to bepositioned in the patient's natural trochlear groove 166.

The base plate 20 also includes a number of customized cavities 70,which are sized to be positioned over regions in the pre-determinedlocation of the bone that may include a defect or are damaged ordifficult to model. In that way, the cavities 70 are sized such thatcontact with those regions may be avoided so as to not interfere withpositioning the cutting block 10 in the pre-determined location andorientation. In the illustrative embodiment, the notch 28 definedbetween the arms 24, 26 is one of the customized cavities. As shown inFIGS. 1-3, the customized cavities 70 also include an aperture 72 thatextends through the bone-facing surface 52 of the anterior flange 50. Asshown in FIGS. 2, the customized cavities 70 also include a pair ofchannels 74, 76 that are defined in the bone-facing surface 52 of theanterior flange 50. In the illustrative embodiment, each channel 74, 76extends from an end 78 that opens into the aperture 72 to an open end 80that is defined in the outer edge of the anterior flange 50.

In the illustrative embodiment, the base plate 20 of the cutting block10 has a low-profile to reduce the size of the incision and reduce theamount of bone displacement needed to position the cutting block 10. Thelow-profile has been customized for block 10 by minimizing thethicknesses of the arms 24, 26 and the anterior flange 50. As shown inFIG. 3, a thickness 82 is defined between the outer surface 48 and thebone-facing surface 36 of each arm. To minimize the thickness 82, theouter surface 48 of each arm is convexly curved to follow the concavecurvature of the bone-facing surface 36. Similarly, as shown in FIG. 4,a thickness 84 is defined between the outer surface 64 and thebone-facing surface 52 of the anterior flange 50, and the outer surface64 of the flange 50 is shaped to follow the geometry of the bone-facingsurface 52 to minimize the thickness 84.

As shown in FIGS. 1-8, each of the surgical tool guide bodies 22 of thecutting block 10 is attached to and extends outwardly from the outersurfaces 48, 64 of the arms 24, 26 and the anterior flange 50 to a freeend 90 that is spaced apart from the base plate 20. In the illustrativeembodiment, the guide bodies 22 include an anterior guide body 100 thatextends anteriorly from the anterior ends of the arms 24, 26 and theanterior flange 50 to its free end 102. The anterior guide body 100includes a distal flange 104 and a pair of bosses 106, 108 that extendproximally from the flange 104. As shown in FIG. 1, the aperture 72defined in the base plate 20 is positioned proximal of the distal flange104 and between the bosses 106, 108.

The distal flange 104 of the anterior guide body 100 includes anelongated opening 110 that is defined in the free end 102 and a numberof inner walls 112 that extend inwardly from the opening 110. As shownin FIG. 2, the inner walls 112 extend to another opening 114 that isdefined in the bone-facing surface 52. As shown in FIGS. 4 and 6-8, theopening 114 extends through the contour 54 of the base plate 20 suchthat the opening 114 is defined by edges 66, 68 of the bone-facingsurface 52, which follow a curved, irregular path that matches the shapeof the patient's femur 16 in that region. The opening 114 cooperateswith the inner walls 112 and the elongated opening 110 to define theguide slot 12, which is sized and shaped to guide a surgical tool suchas, for example, a cutting blade, into engagement with the patient'sbone. As described above, the cutting guide slot 12 is positioned toguide a customized, patient-specific resection of a distal end 14 of apatient's femur 16. Because the edge 66 follows the shape of thepatient's femur and the posterior tip of the edge 66 extends into thepatient's trochlear groove, the cutting guide slot 12 provides supportfor the cutting blade in close proximity to the region under resection.

As shown in FIG. 1, each of the bosses 106, 108 extend from a proximalsurface 116 of the distal flange 104 to a curved proximal end 118. Itshould be appreciated that in other embodiments one or both of thebosses 106, 108 may be spaced apart from the distal flange 104, therebyforming separate guide bodies. An opening 120 is defined in the free end102 of each of the bosses 106, 108 adjacent to the proximal end 118. Aninner wall 122 extends inwardly from the opening 120. As shown in FIG.2, each inner wall 122 extends to another opening 124 that opens intoone of the channels 74, 76 to define a guide slot 126 extending throughthe cutting block 10. In the illustrative embodiment, each guide slot126 is a drill guide and fixation pin guide hole, which is sized andshaped to guide a surgical drill to prepare the patient's bone toreceive a fixation pin to couple to the block 10 to the bone.

Referring now to FIGS. 9-10, the guide bodies 22 include a pair ofposterior guide bosses 140, which are attached to, and extend distallyfrom, the outer surfaces 48 of the arms 24, 26, respectively. Eachposterior guide boss 140 includes a guide slot 142 that is sized andshaped to guide surgical drill and a fixation pin into engagement withthe patient's bone to couple to the block 10 to the bone. Each guideboss 140 includes a post 144 that extends from a base 146 attached tothe outer surface 48 of one of the arms 24, 26 to a free end 148 that isspaced apart from the outer surface 48.

As shown in FIGS. 9 and 10, the base 146 is wider in theanterior-posterior direction than the free end 148. Each post 144 alsoincludes a convex curved posterior surface 150 that extendssubstantially orthogonal to the arm outer surface 48. In theillustrative embodiment, each post 144 also includes a curved taperedanterior surface 152 that extends obliquely relative to the arm outersurface 48. The curved tapered anterior surface 152 improves themanufacturability of the cutting block 10 by eliminating a flat,horizontal surface, which, during fabrication, would face downward andrequire a support structure.

Returning to FIG. 8, an opening 154 is defined in the free end 148 ofeach boss 140. An inner wall 156 extends inwardly from the opening 154to another opening 158 that is defined in a bone-facing surface 36 ofone of the arms 24, 26. The openings 154, 158 and inner wall 156cooperate to define the guide slot 142. As described above, each guideslot 142 is a drill guide and fixation pin guide hole, which is sizedand shaped to guide a surgical drill or self-drilling fixation pin toprepare the patient's bone to receive a fixation pin to couple to theblock 10 to the bone.

As shown in FIG. 8, the inner walls 112, 122, 156 define a number ofrelief sections 160, 162, 164 in the guide slots 12, 126, 142,respectively, of the cutting block 10. Each of the relief sections 160,162, 164 is larger (e.g., wider) than the rest of the guide slots 12,126, 142 to improve manufacturability.

Referring now to FIGS. 11A-B, a routine 200 for fabricating thecustomized patient-specific orthopaedic surgical instrument 10 isillustrated. The method 200 includes process steps 212 and 214, in whichan orthopaedic surgeon performs pre-operative planning of theorthopaedic surgical procedure to be performed on a patient. The processsteps 212 and 214 may be performed in any order or contemporaneouslywith each other. In process step 212, a number of medical images of therelevant portions of a patient's bone are generated. For example, for aknee replacement surgery, the medical images may include images of thedistal end of a patient's femur and the proximal end of a patient'stibia. For a hip replacement surgery, the medical images may includeimages of the patient's acetabulum and surrounding bony anatomy, as wellas images of the proximal end of the patient's femur. To do so, theorthopaedic surgeon or other healthcare provider may operate an imagingsystem to generate the medical images. The medical images may beembodied as any number and type of medical images capable of being usedto generate a three-dimensional rendered model of the patient'sacetabulum and surrounding bony anatomy. For example, the medical imagesmay be embodied as any number of computed tomography (CT) images,magnetic resonance imaging (MRI) images, or other three-dimensionalmedical images. Additionally, or alternatively, as discussed in moredetail below in regard to process step 216, the medical images may beembodied as a number of X-ray images or other two-dimensional imagesfrom which a three-dimensional rendered model of the relevant area ofthe patient's bone.

In process step 214, the orthopaedic surgeon may determine anyadditional pre-operative constraint data. The constraint data may bebased on the orthopaedic surgeon's preferences, preferences of thepatient, anatomical aspects of the patient, guidelines established bythe healthcare facility, or the like. For example, in a knee replacementsurgery, the constraint data may include the type and size of the kneeprosthesis, the amount of distal and posterior resections to beperformed on the patient's femur and so forth. In a hip replacementsurgery, the constraint data may include the orthopaedic surgeon'spreference for the amount of inclination and version for an acetabularprosthesis, the amount of the bone to ream, the size range of theorthopaedic implant, and/or the like. In some embodiments, theorthopaedic surgeon's preferences are saved as a surgeon's profile,which may be used as a default constraint values for further surgicalplans.

The medical images and the constraint data, if any, may be transmittedor otherwise provided to an orthopaedic surgical instrument vendor ormanufacturer for processing the images. The orthopaedic surgicalinstrument vendor or manufacturer processes the medical images in step216 to facilitate the determination of the proper resection planes,instrument location, implant sizing, and fabrication of the customizedpatient-specific orthopaedic surgical instrument as discussed in moredetail below. The images may also be processed on-site at the hospital,for example, or the surgeon's offices.

In process step 218, three-dimensional images may be converted orotherwise generated from the medical images. For example, in embodimentswherein the medical images are embodied as a number of two-dimensionalimages, the vendor may use a suitable computer algorithm to generate oneor more three-dimensional images form the number of two-dimensionalimages. Additionally, in some embodiments, the medical images may begenerated based on an established standard such as the Digital Imagingand Communications in Medicine (DICOM) standard. In such embodiments, anedge-detection, thresholding, watershed, or shape-matching algorithm maybe used to convert or reconstruct images to a format acceptable in acomputer aided design application or other image processing application.

In process step 220, the medical images, and/or theconverted/reconstructed images from process step 218 may be processed,to determine a number of aspects related to the bony anatomy of thepatient such as the anatomical axis of the patient's bones, themechanical axis of the patient's bone, other axes and various landmarks,and/or other aspects of the patient's bony anatomy. Any suitablealgorithm may be used to process the images. In some embodiments, athree-dimensional model of the patient's bone including athree-dimensional rendering of the bone may be generated from theprocessed images. One such three-dimensional bone model is the femoralbone model 170 is shown in FIGS. 12-15, which are referenced below.

In process step 222, a surgeon, vendor, or other user may identify oneor more problematic regions of the bone to avoid using thethree-dimensional model. Such regions may include osteophytes, damagedregions of the bone, undercuts that would cause the instrument to getstuck on the bone, or other regions that are known to be difficult tomodel based on the medical images. One such region may include a portionof the patient's trochlear groove. As shown in FIG. 12, the user mayoutline an outer edge 172 of one such region 174 on the distal end 14 ofa patient's femur 16 using the femoral bone model 170. The user may alsocreate a raised or offset surface 176 within the outer edge 172 todefine a desired location of a cavity 70 of the orthopaedic surgicalinstrument.

The routine 200 may advance to process step 224 in which an outerboundary 178 of the patient-specific orthopaedic surgical instrument isdefined on the femoral bone model 170. As shown in FIG. 13, the outerboundary 178 defines the outer edge of the planned surgical instrument,which may be, for example, the femoral cutting block 10 described above.The boundary 178 identifies the locations and shapes of the arms 24, 26as well as the location and shape of the anterior flange 50 of the baseplate 20 of the cutting block 10.

In process step 226, a model of the customized patient-specificorthopaedic surgical instrument is generated. In some embodiments, themodel is embodied as a three-dimensional rendering of the customizedpatient-specific orthopaedic surgical instrument. In other embodiments,the model may be embodied as a mock-up or fast prototype of thecustomized patient-specific orthopaedic surgical instrument. Thepatient-specific orthopaedic surgical instrument to be modeled andfabricated may be determined based on the orthopaedic surgical procedureto be performed, the constraint data, and/or the type of orthopaedicprosthesis to be implanted in the patient.

The particular shape of the customized patient-specific orthopaedicsurgical instrument is determined based on the planned location andimplantation angles of the orthopaedic prosthesis relative to thepatient's bone. Additionally, the planned location of the orthopaedicsurgical instrument may be based on the identified landmarks of thepatient's bone identified in process step 220.

In some embodiments, the particular shape or configuration of thecustomized patient-specific orthopaedic surgical instrument may bedetermined based on the planned location of the instrument relative tothe patient's bony anatomy. That is, the customized patient-specificorthopaedic surgical instrument may include a bone-facing surface havinga negative contour that matches the corresponding contour of a portionof the bony anatomy of the patient such that the orthopaedic surgicalinstrument may be coupled to the bony anatomy of the patient in a uniquelocation, which corresponds to the pre-planned location for theinstrument. Such negative contours may include a unique set of ridgesand depressions shaped to match a corresponding set of ridges anddepressions on the patient' bone. When the orthopaedic surgicalinstrument is coupled to the patient's bony anatomy in the uniquelocation, one or more guides (e.g., cutting or drilling guide) of theorthopaedic surgical instrument may be aligned to the inclination andversion planes, as discussed above.

The process sub-steps 228-234 shown in FIG. 11B outline an exemplarysub-routine that may be followed to generate the model of thepatient-specific orthopaedic surgical instrument. In process sub-step228, the femoral bone model 170 may be used to generate the customizedpatient-specific negative contour or contours of the patient-specificsurgical instrument. To do so, the user may create an infinitely thinsheet 180 within the boundary 178 shown in FIG. 13. The thin sheet 180may include the depressions and ridges to be included in the negativecontour of the patient-specific surgical instrument.

In process sub-step 230, the user may add thickness to the sheet 180within the boundary 178 to generate the outer surface of the customizedpatient-specific surgical instrument and thereby define the base plateof the instrument. As discussed above, the user may minimize thethickness of the instrument to reduce the size of the incision necessaryto place the instrument on the patient's bone. In process sub-step 232,the user may define a cavity 70 over each of the problematic regions 174identified in process step 222. As part of defining the cavity orcavities, the user may adjust the shape and size of the planned baseplate to adjust the planned size and/or weight of the instrument. Eachcavity may have an outer edge that is aligned with the edge 172 of theregion 174.

In process sub-step 234, the user may position the surgical instrumentguide bodies in position on the femoral bone model 170 to create themodel 182 of the patient-specific orthopaedic surgical instrument shownin FIG. 15. To do so, the desired cutting planes for implantation of theorthopaedic prosthesis may be determined. The planned cutting planes maybe determined based on the type, size, and position of the orthopaedicprosthesis to be used during the orthopaedic surgical procedure; theprocess images, such as specific landmarks identified in the images; andthe constraint data supplied by the orthopaedic surgeon in process steps212 and 214. The type and/or size of the orthopaedic prosthesis may bedetermined based on the patient's anatomy and the constraint data. Forexample, the constraint data may dictate the type, make, model, size, orother characteristic of the orthopaedic prosthesis. The selection of theorthopaedic prosthesis may also be modified based on the medical imagessuch that an orthopaedic prosthesis that is usable with the bone of thepatient and that matches the constraint data or preferences of theorthopaedic surgeon is selected.

When positioning the guide bodies on the femoral bone model 170, theuser may adjust the size, shape, and location of each guide body asneeded. As shown in FIGS. 14-15, the user may include a cutting guideslot and one or more drill guide slots for preparing the patient's boneto receive a fixation pin. The orientation of the drill guide slots maybe based on the planned resection planes and may be adjusted tofacilitate the resection of the patient's bone. As shown in FIGS. 14-15,the guide bodies for the guide slots may be formed by extending thebodies outwardly from the outer surface of the model 182 to their freeends.

It should be appreciated that the sub-steps 228, 230, 232, 234 may beperformed in an order different from that described above. For example,a user may choose to identify the planned resection plane first andinsert the cutting guide body into the femoral bone model prior togenerating the customized patient-specific negative contour.Additionally, in some embodiments, one or more of the sub-steps may beomitted.

After the model of the customized patient-specific orthopaedic surgicalinstrument has been generated in process step 226, the model isvalidated in process step 236. The model may be validated by, forexample, analyzing the rendered model while coupled to thethree-dimensional model of the patient's anatomy to verify thecorrelation of cutting guides, reaming guides, inclination and versionplanes, and/or the like. Additionally, the model may be validated bytransmitting or otherwise providing the model generated in step 226 tothe orthopaedic surgeon for review.

After the model has been validated in process step 236, the customizedpatient-specific orthopaedic surgical instrument is fabricated inprocess step 238. As described above, the customized patient-specificorthopaedic surgical instrument may be formed by DMLS, which, asdescribed above, is a form of 3-D printing technology. In DMLS, theorthopaedic surgical instrument is formed in a layer-by-layer fashionusing laser sintering in which light fuses metallic powder, forming themetallic structures that define the orthopaedic surgical instrument. Aspart of the process of fabricating the orthopaedic surgical instrument,the metallic powder may be fused in layers, resulting in an orthopaedicsurgical instrument that is a single monolithic component that includesa plurality of fused laminations 184. For example, as shown in FIG. 8,the cutting block 10 includes a plurality of fused laminations 184 ofmetallic material of uniform thickness. It should be appreciated thatother forms of 3-D printing technology such as, for example, opticalfabrication, photo-solidification, or resin printing may be used tofabricate the orthopaedic surgical instrument.

As described above, the cutting block 10 includes a pair of guide bosses140 that have tapered anterior surfaces 152. In one exemplary process,the cutting block 10 may be fabricated with the anterior elongatedopening 110 cutting slot 12 pointing downward. By tapering the anteriorsurfaces 152, no support structure is needed to keep the bosses 140 fromcollapsing during fabrication. It should be appreciated that othersurfaces that face downward during the build may be tapered/angled tominimize the amount of support structure needed. In the illustrativeembodiment, the tapered surfaces 152 are angled by about 35 degrees. Asused herein, the term “about” should be understood to refer to permitthe normal tolerances created by manufacturing variation and otherdesign criteria.

After the customized patient-specific orthopaedic surgical instrument isfabricated, the surgeon may perform the orthopaedic surgical procedureusing the customized patient-specific orthopaedic surgical instrument.As discussed above, because the orthopaedic surgeon does not need todetermine the proper location of the orthopaedic surgical instrumentintra-operatively, which typically requires some amount of estimation onpart of the surgeon, the guesswork and/or intra-operativedecision-making on part of the orthopaedic surgeon is reduced.

It should also be appreciated that variations in the bony of anatomy ofthe patient may require more than one customized patient-specificorthopaedic surgical instrument to be fabricated according to the methoddescribed herein. For example, the patient may require the implantationof two orthopaedic prostheses. As such, the surgeon may follow themethod 200 of FIGS. 11A-B to fabricate a different customizedpatient-specific orthopaedic surgical instrument for use in replacingeach portion of the patient's bony anatomy. Each customizedpatient-specific orthopaedic surgical instrument defines a cutting planeor other relevant parameter relative to each bone that is different dueto the variation in the bony anatomy.

One such instrument—a customized patient-specific tibial cutting block310—is shown in FIGS. 16-22. The tibial cutting block 310 includes acutting guide slot 312 position to guide a customized, patient-specificresection of a proximal end of a patient's tibia along a predeterminedresection plane. As described in greater detail below, the tibialcutting block 310 is configured to be coupled to a patient's tibia in aunique pre-determined location and orientation. It illustrativeembodiment, the structure of the cutting block 310, like the structureof the femoral cutting block 10 described above, has been contoured toreduce its size relative to conventional cutting blocks and avoidcontact with undesirable regions of the patient's bone.

As shown in FIG. 16, the tibial cutting block 310 includes a base plate320 and a number of surgical tool guide bodies 322 that are attached to,and extend outwardly from, the base plate 320. Like the femoral cuttingblock 10, the tibial cutting block 310 is a single monolithic componentformed via a 3-D printing process from a metallic material such as, forexample, stainless steel. In the illustrative embodiment, the base plate320 includes a pair of arms 324, 326 that are configured to engage aproximal end of the patient's tibia. The arms 324, 326 are spaced apartfrom each other such that a notch 328 is defined between theirrespective inner edges. The notch 328 is sized and shaped to receive thenatural spine of the patient's tibia. In that way, base plate 320 isshaped to engage the medial and lateral tibial compartments of thepatient's natural tibia in avoid contact with the spine.

Each of the arms 324, 326 includes a bone-facing surface 336 thatengages the medial or lateral tibial compartment. As shown in FIG. 19,each bone-facing surface 336 includes a negative contour 338 that isconfigured to receive a portion of the patient's tibia. Each contour 338includes a unique set of ridges 340 and depressions 342 that are shapedto engage a corresponding set of depressions and ridges of the patient'stibia. Each of the arms 324, 326 also includes an outer surface 344 thatis positioned opposite the corresponding bone-facing surface 336. In theillustrative embodiment, a plurality of apertures 346 extend through thesurfaces 336, 344. Each aperture 346 is illustratively diamond-shapedand includes edges that are configured to grip the bone.

The base plate 320 also includes an anterior flange 350 that isconfigured to engage the proximal end of the patient's tibia. As shownin FIG. 17, the anterior flange 350 includes a bone-facing surface 352,and a negative contour 354 is defined in the bone-facing surface 352.The negative contour 354 is configured to receive a portion of thepatient's tibia in includes a unique set of ridges 356 and depressions358 that are shaped to engage a corresponding set of depressions andridges of the patient's tibia. The anterior flange 350 also includes anouter surface 364 that is positioned opposite the bone-facing surface352. In the illustrative embodiment, a plurality of apertures 346 alsoextend through the surfaces 352, 364. Each aperture 346 isillustratively diamond-shaped and includes edges that are configured togrip the bone. It should be appreciated that in other embodiments theapertures may have different geometric shapes or may be omitted.Similarly, it should be appreciated that the femoral cutting block 10described above may, in other embodiments, include such apertures.

In the illustrative embodiment, the notch 328 defined between the arms324, 326 is a customized cavity similar to the customized cavity 70described above in regard to the femoral cutting block 10. It shouldalso be appreciated that in other embodiments the base plate 320 mayinclude additional customized cavities similar to the customizedcavities 70. Such cavities may be sized and shaped to be positioned overproblematic regions of the patient's tibia in the pre-determinedlocation of the bone such that those regions may be avoided so as to notinterfere with the positioning of the cutting block 310.

In the illustrative embodiment, the base plate 320 of the cutting block310 also has a low-profile to reduce the size of the incision and reducethe amount of bone displacement needed to position the cutting block310. The low-profile has been customized for block 310 by minimizing thethicknesses of the arms 324, 326 and the anterior flange 350. As shownin FIG. 17, a thickness 382 is defined between the outer surface 348 andthe bone-facing surface 336 of each arm. The outer surfaces 348 areshaped to follow the geometries of the bone-facing surfaces 336 of thearms 324, 326. Similarly, as shown in FIG. 19, a thickness 384 isdefined between the outer surface 364 and the bone-facing surface 352 ofthe anterior flange 350, and the outer surface 364 of the flange 350 isshaped to follow the geometry of the bone-facing surface 352 to minimizethe thickness 384.

As shown in FIGS. 16-22, each of the surgical tool guide bodies 322 ofthe cutting block 310 is attached to and extends outwardly from theouter surfaces 348, 364 of the arms 324, 326 and the anterior flange 350to a free end 390 that is spaced apart from the base plate 320. In theillustrative embodiment, the guide bodies 322 include an elongated body400 and a pair of bosses 402, 404 that extend outwardly from theanterior flange 350. The elongated body 400 includes an elongatedopening 410 that is defined in its free end 390, and a number of innerwalls 412 extend inwardly from the opening 410. As shown in FIG. 17, theinner walls 412 extend to another opening 414 that is defined by an edge416 of the bone-facing surface 352. The edge 416 illustratively followsa curved path to match the shape of the patient's tibia in that region.The opening 414 cooperates with the inner walls 412 and the elongatedopening 410 to define the guide slot 312, which is sized and shaped toguide a surgical tool such as, for example, a cutting blade, intoengagement with the patient's bone. As described above, the cuttingguide slot 312 is positioned to guide a customized, patient-specificresection of the proximal end of a patient's tibia. Because the edge 416follows the shape of the patient's tibia, the cutting guide slot 312provides support for the cutting blade in close proximity to the regionunder resection.

As shown in FIG. 16, each of the bosses 402, 404 are positioned distalof the elongated body 400. An opening 420 is defined in the free end 390of each of the bosses 402, 404, and an inner wall 422 extends inwardlyfrom the opening 420. As shown in FIG. 17, each inner wall 422 extendsto another opening 424 in the bone-facing surface 352 to define a guideslot 426 extending through the cutting block 310. In the illustrativeembodiment, each guide slot 426 is a drill guide and fixation pin guidehole, which is sized and shaped to guide a surgical drill to prepare thepatient's bone to receive a fixation pin to couple to the block 310 tothe bone.

Another customized patient-specific orthopaedic surgical instrument thatmay be modeled and fabricated using the routine 200 is the customizedpatient-specific anterior-posterior chamfer cutting block 510 shown inFIGS. 23-30. The cutting block 510 includes a base plate 512 that hasbeen customized to fit a distal end 514 of a patient's femur 16 that hasbeen resected using, for example, the femoral cutting block 10 describedabove. The cutting block 510 also includes a plurality of surgical toolguide bodies 516, which are attached to an extend outwardly from thebase plate 512 and which are configured to guide surgical tools intocontact with the patient's femur, as described in greater detail below.In the illustrative embodiment, the cutting block 510 is a singlemonolithic component form from a metallic material such as, for example,stainless steel. In that way, the base plate 512 and the guide bodies516 form a single monolithic metallic block. Like the cutting blocks 10,310, the cutting block 510 is formed by DMLS. As shown in FIG. 27, thecutting block 510 includes a plurality of fused laminations 184 ofmetallic material of uniform thickness.

The base plate 512 includes a bone-facing surface 520 and an outersurface 522 that is positioned opposite the bone-facing surface 520. Anouter wall 524 extends between the surfaces 520, 522 to define the outerperimeter of the base plate 512. As shown in FIG. 25, the bone-facingsurface 520 includes an outer edge 526 that is connected to the outerwall 524 and has been customized to match an outer edge 528 (see FIG.28) of the resected distal end 514 of a patient's femur 16. In that way,the cutting block 510 is configured to be coupled to the patient's femur16 in a unique pre-determined location and orientation.

The outer edge 526 includes a superior section 530 that defines a notch532 in the base plate 512. In the illustrative embodiment, the superiorsection 530 is curved to match the curvature of the anterior edgesection 534 (see FIG. 28) of the resected distal end 514 of a patient'sfemur 16. The outer edge 526 of the bone-facing surface 520 alsoincludes an inferior section 540 that defines a notch 542 in the baseplate 512. In the illustrative embodiment, the inferior section 540 iscurved to match the curvature of the posterior edge section 544 (seeFIG. 28) of the resected distal end 514 of a patient's femur 16, and theshape of the notch 532 substantially matches the shape of the edge ofthe intercondylar notch 30.

In the illustrative embodiment, the base plate 512 of the cutting block510 has a low-profile to reduce the size of the incision and reduce theamount of bone displacement needed to position the cutting block 510.Similar to the blocks 10, 310, the low-profile has been customized forblock 510 by minimizing the thickness of the base plate 512 definedbetween the outer surface 522 and the bone-facing surface 520.

As shown in FIGS. 22-27, each of the surgical tool guide bodies 516 ofthe cutting block 510 is attached to and extends outwardly from theouter surface 522 to an outer end 550 that is spaced apart from the baseplate 512. In the illustrative embodiment, the guide bodies 516 includean anterior resection guide body 560 that is positioned over the notch532 of the base plate 512. The resection guide body 560 includes anelongated opening 562 that is defined in its outer end 550, which is afree end spaced apart from the outer ends of the other guide bodies 516.The resection guide body 560 also includes a number of inner walls 564that extend inwardly from the opening 562. As shown in FIG. 25, theinner walls 564 extend to an opening 566 that opens into the superiornotch 532 of the base plate 512. The opening 566 cooperates with theinner walls 564 and the elongated opening 562 to define the guide slot568, which is sized and shaped to guide a surgical tool such as, forexample, a cutting blade, into engagement with the patient's femur andguide the anterior resection of the femur along a predeterminedresection plane. The cutting guide slot 568 is positioned in a unique,predetermined position and orientation that has been customized for thatpatient.

The guide bodies 516 include a posterior resection guide body 570 thatis positioned over the inferior notch 542 of the base plate 512. Theresection guide body 570 includes an elongated opening 572 that isdefined in its outer end 550, which is a free end spaced apart from theouter ends of the other guide bodies 516. The resection guide body 570also includes a number of inner walls 574 that extend inwardly from theopening 572. As shown in FIG. 25, the inner walls 574 extend to anopening 576 that opens into the inferior notch 542 of the base plate512. The opening 576 cooperates with the inner walls 574 and theelongated opening 572 to define the guide slot 578, which is sized andshaped to guide a surgical tool such as, for example, a cutting blade,into engagement with the patient's femur and guide the posteriorresection of the femur along a predetermined resection plane. Thecutting guide slot 568 is positioned in a unique, predetermined positionand orientation that has been customized for that patient.

The guide bodies 516 also include a pair of chamfer resection guidebodies 580, 590 that are positioned between the anterior and posteriorresection guide bodies 560, 570. The resection guide body 580 includesan elongated opening 582 that is defined in its outer end 550, and anumber of inner walls 584 that extend inwardly from the opening 582. Asshown in FIG. 25, the inner walls 584 extend to an opening 586 definedin the bone-facing surface 520 of the base plate 512. The opening 586cooperates with the inner walls 584 and the elongated opening 582 todefine a chamfer resection guide slot 588, which is sized and shaped toguide a surgical tool such as, for example, a cutting blade, intoengagement with the patient's femur and guide a chamfer resection of thefemur along a predetermined resection plane, which extends at an anglerelative to the resection planes defined by the other cutting guideslots. The cutting guide slot 588 is positioned in a unique,predetermined position and orientation that has been customized for thatpatient.

The resection guide body 590 includes an elongated opening 592 that isdefined in its outer end 550, and a number of inner walls 594 thatextend inwardly from the opening 592. As shown in FIG. 25, the innerwalls 594 extend to an opening 596 defined in the bone-facing surface520 of the base plate 512. The opening 596 cooperates with the innerwalls 594 and the elongated opening 592 to define another chamfer guideslot 598, which is sized and shaped to guide a surgical tool such as,for example, a cutting blade, into engagement with the patient's femurand guide another chamfer resection of the femur along a predeterminedresection plane, which also extends at an angle relative to theresection planes defined by the other cutting guide slots. The cuttingguide slot 598 is positioned in a unique, predetermined position andorientation that has been customized for that patient.

As shown in FIGS. 22-27, the outer ends 550 of the chamfer resectionguide bodies 580, 590 are coupled together, and a passageway 600 isdefined between the surfaces of the guide bodies 580, 590 and the baseplate 512. In the illustrative embodiment, the passageway 600 has atriangular cross-section. As shown in FIG. 27, the guide slots 588, 598of the guide bodies 580, 590 intersect, and the inner walls 584, 594 ofthe guide bodies 580, 590 include a number of openings 602 at theintersection such that the guide slots 588, 598 are in communicationwith each other.

The guide bodies 516 also include a pair of bosses 604, 606 that extendoutwardly from the base plate 512 between the chamfer resection guidebodies 580, 590 and the posterior resection guide body 570. An opening610 is defined in the outer end 550 of each of the bosses 604, 606, andan inner wall 612 extends inwardly from the opening 610. As shown inFIG. 17, each inner wall 612 extends to another opening 614 in thebone-facing surface 520 to define a guide slot 616 extending through thecutting block 510. In the illustrative embodiment, each guide slot 616is a drill guide and fixation pin guide hole, which is sized and shapedto guide a surgical drill to prepare the patient's bone to receive afixation pin to couple to the block 510 to the patient's femur.

As described above, the cutting block A-P chamfer cutting block 510 iscustomized to fit a resected distal end 514 of a patient's femur 16,which is shown in FIG. 28. The resected distal end 514 includes aresected distal surface 620 that is bounded by the outer edge 528. Asshown in FIG. 28, the outer edge 528 includes an anterior edge section534 that defines the distal opening of the patient's trochlear groove166 and a posterior edge section 544 that defines the distal opening ofthe patient's intercondylar notch 30. In the illustrative embodiment,the size and shape of the resected distal surface 620 is pre-operativelyplanned during, for example, the execution of the routine 200. In otherwords, when the surgeon or other user defines the distal resection planeto be created using the cutting block 10, the size and shape of theresected distal surface 620 is also modeled. With the model of theresected distal surface 620, the user may generate a 3-D computer modelof the A-P chamfer cutting guide block 510 during the process step 226of the routine 200.

As shown in FIG. 29 and described above, the outer edge 526 of the baseplate 512 of the cutting block 510 is shaped to match the outer edge 528of the resected distal surface 620. In particular, the superior section530 of the plate outer edge 526 is curved to match the curvature of theanterior edge section 534 of the outer edge 528 of the resected distalsurface 620, and the inferior section 540 of the plate outer edge 526 iscurved to match the curvature of the posterior edge section 544 of theouter edge 528 of the resected distal surface 620. The superior notch532 of the base plate 512 is shaped to match the distal opening of thepatient's trochlear groove 166. The base plate 512 also includes theinferior notch 542 that is shaped to match the distal opening of thepatient's intercondylar notch 30. As shown in FIG. 30, the outer edges526, 528 of the block and bone are coincident when the cutting block 510is properly positioned on the patient's bone, with the notches 532, 542aligned with the distal openings of the groove 166 and the notch 30. Inthat way, the surgeon or other user are informed when the block isproperly positioned and any misalignment with the patient's bone can becorrected prior to beginning any resection with the block 510.

Referring now to FIGS. 31-37, another embodiment of a customizedpatient-specific femoral cutting block (hereinafter the cutting block710) is shown. The embodiment of FIGS. 31-37 includes many features thatare the same or similar to features shown in the embodiment of FIGS.1-10. Similar features will be identified in FIGS. 31-37 with the samereference numbers as were used in FIGS. 1-10. The cutting block 710includes a cutting guide slot 712 positioned to guide a customized,patient-specific resection of a distal end of a patient's femur. Asdescribed in greater detail below, the femoral cutting block 710 isconfigured to be coupled to the patient's femur in a uniquepre-determined location and orientation. In the illustrative embodiment,the structure of the cutting block 710 has been contoured to reduce itssize relative to conventional cutting blocks and avoid contact withundesirable regions of the patient's bone.

As shown in FIG. 31, the femoral cutting block 710 includes a base plate720 and a number of surgical tool guide bodies 722 that are attached to,and extend outwardly from, the base plate 720. In the illustrativeembodiment, the femoral cutting block 710 is a single monolithiccomponent formed from a metallic material such as, for example,stainless steel, via a DMLS technique. In that way, the base plate 720and the guide bodies 722 form a single monolithic metallic block.

The base plate 720 includes a posterior section including a pair of arms24, 26 that are configured to engage the distal end of the patient'sfemur. The arms 24, 26 are spaced apart from each other such that anotch 28 is defined between the inner edges of the arms 24, 26. Thenotch 28 is sized and shaped to correspond to the natural intercondylarnotch of the patient's femur. In that way, contact within bone surfaceswith the natural intercondylar notch 30, which may be difficult tomodel, is avoided.

Each of the arms 24, 26 has a bone-contacting or bone-facing surface 36that engages one of the natural condyles 32, 34. In the illustrativeembodiment, each bone-facing surface 36 includes a number of negativecontours 38 that are configured to receive a portion of the naturalcondyles 32, 34. Each of the arms 24, 26 also includes an outer surface48 that is positioned opposite its corresponding bone-facing surface 36.In the illustrative embodiment, each outer surface 48 is substantiallysmooth.

As shown in FIG. 31, the base plate 720 also includes an anteriorsection including an anterior flange 750 that is configured to engagethe distal end of the patient's femur. In the illustrative embodiment,the flange 750 is spaced apart from the arms 24, 26. The anterior flange750 includes a bone-facing surface 752 that includes a number ofnegative contours 754 that are configured to receive a portion of thepatient's femur. As shown in, for example, FIGS. 32 and 34, the contour754 of the anterior flange 750 has a unique set of ridges 756 anddepressions 758 that are shaped to engage a corresponding unique set ofdepressions and ridges of the patient's femur. The anterior flange 750also includes an outer surface 764 that is positioned opposite thebone-facing surface 752. In the illustrative embodiment, the outersurface 764 is substantially smooth.

The base plate 720 also includes a number of customized cavities 70,which are sized to be positioned over regions in the pre-determinedlocation of the bone that may include a defect or are damaged ordifficult to model. In that way, the cavities 70 are sized such thatcontact with those regions may be avoided so as to not interfere withpositioning the cutting block 10 in the pre-determined location andorientation. In the illustrative embodiment, the notch 28 definedbetween the arms 24, 26 is one of the customized cavities. As shown inFIGS. 31-33, the customized cavities 70 also include an aperture 772that extends through the bone-facing surface 752 of the anterior flange750. As shown in FIGS. 31-32, the customized cavities 70 also include apair of channels 74, 76 that are defined in the bone-facing surface 752of the anterior flange 750.

As described above, the cutting block 710 includes a number of surgicaltool guide bodies 722 configured to guide a surgical tool into contactwith the patient's bone. In the illustrative embodiment, the guidebodies 722 include a distal resection guide body 780 that extendsanteriorly from the anterior ends of the arms 24, 26. The distalresection guide body 780 includes an elongated opening 782 that isdefined in its outer end 784 and a number of inner walls 786 that extendinwardly from the opening 782. As shown in FIG. 32, the inner walls 786extend to another opening 788 that is defined in the bone-facing surface762. The opening 788 cooperates with the inner walls 786 and theelongated opening 782 to define the cutting guide slot 712, which issized and shaped to guide a surgical tool such as, for example, acutting blade, into engagement with the patient's bone. As describedabove, the cutting guide slot 712 is positioned to guide a customized,patient-specific resection of a distal end of a patient's femur.

As shown in FIG. 35, the inner walls 786 include a medial inner wall 790that defines the medial side of the guide slot 712 and a lateral innerwall 792 that defines the lateral side of the guide slot 712. In theillustrative embodiment, the lateral inner wall 792 extends at anoblique angle relative to the medial inner wall 790 to guide theresection of the patient's bone. The oblique angle, like the rest of thecutting guide block 710, is customized to the bony anatomy of thepatient. It should be appreciated that the medial inner wall may beangled in other embodiments.

The tool guide bodies 722 of the block 710 also includes a pair of guidebosses 796, 798 that are integrated into the anterior flange 750, whichextends proximally from the guide body 780. An opening 800 is defined inthe outer surface 802 of each of the bosses 796, 798, and an inner wall804 extends inwardly from the opening 800. As shown in FIG. 32, eachinner wall 804 extends to another opening 806 that opens into one of thechannels 74, 76 to define a guide slot 808 extending through the cuttingblock 710. In the illustrative embodiment, each guide slot 808 is adrill guide and fixation pin guide hole, which is sized and shaped toguide a surgical drill to prepare the patient's bone to receive afixation pin to couple to the block 710 to the bone.

The cutting block 710 has a low-profile to reduce the size of theincision and reduce the amount of bone displacement needed to positionthe cutting block 710. The low-profile has been customized for block 710by adjusting the shape and sizes of the base plate and the guide bodies.For example, as shown in FIG. 36, the guide boss 796 has a length 810that is shorter than the length 812 of the guide boss 798, which isshown in FIG. 36. Similarly, the outer surface 48 of each arm isconvexly curved to follow the concave curvature of the bone-facingsurface 36 of the arm.

The guide bodies 722 of the cutting block 710 also include a pair ofposterior guide bosses 140, which are attached to, and extend distallyfrom, the outer surfaces 48 of the arms 24, 26, respectively. Eachposterior guide boss 140 includes a guide slot 142 that is sized andshaped to guide surgical drill and a fixation pin into engagement withthe patient's bone to couple to the block 710 to the bone.

Referring now to FIGS. 38-41, other embodiments of customizedpatient-specific cutting blocks (hereinafter the cutting block 910,1010, 1110) are shown. The embodiments of FIGS. 38-41 include manyfeatures that are the same or similar to features shown in theembodiments described above. Similar features will be identified inFIGS. 38-41 with the same reference numbers as were used in reference tothe embodiments above. Referring now to FIG. 38, the cutting block 910includes a cutting guide slot 912 positioned to guide a customized,patient-specific resection of a distal end of a patient's femur. In theillustrative embodiment, the cutting block 910 includes a number ofbone-facing surfaces 916 that have negative contours 38 that areconfigured to receive portions of the patient's bone.

Similar to the tibial cutting block 310, the cutting block 910 includesa plurality of apertures 914 that extend through the bone-facingsurfaces 916 and the outer surfaces 918 of the cutting block 910. Eachaperture 914 is illustratively cylindrical in shape and includes acircular edge that is configured to grip the bone. The apertures 914also extend through the surfaces of the anterior resection guide body920 and open into the guide slot 912. In that way, the apertures 914provide viewing windows for the surgeon or other user to monitor themovement of the cutting saw blade and review the fit of the block 910 onthe bone. It should be appreciated that similar apertures may beincorporated into any of the embodiments described herein. Additionally,it should be appreciated that the apertures may take other sizes andshapes depending on the nature of the patient's bony anatomy.

The cutting block 910 includes a number of other surgical tool guidebodies 920. In the illustrative embodiment, each of the tool guidebodies 920 is a drill guide and fixation guide configured to guide afixation pin into engagement with a patient's bone to couple the cuttingblock 910 to the bone.

Referring now to FIG. 39, the cutting block 1010 includes a cuttingguide slot 1012 positioned to guide a customized, patient-specificresection of a distal end of a patient's femur. In the illustrativeembodiment, the cutting block 1010 includes a number of bone-facingsurfaces 1016 that have negative contours 38 that are configured toreceive portions of the patient's bone.

Similar to the cutting block 710, the cutting block 1010 includes adistal resection guide body 1020 includes an elongated opening 1022 thatis defined in its free end 1024 and a number of inner walls 1026 thatextend inwardly from the opening 1022 to define the cutting guide slot1012, which is sized and shaped to guide a surgical tool such as, forexample, a cutting blade, into engagement with the patient's bone.

As shown in FIG. 39, the inner walls 1026 include a medial inner wall1030 that defines the medial side of the guide slot 1012 and a lateralinner wall 1032 that defines the lateral side of the guide slot 1012. Inthe illustrative embodiment, the lateral inner wall 1032 extends at anoblique angle relative to the medial inner wall 1030 to guide theresection of the patient's bone. The oblique angle, like the rest of thecutting guide block 1010, is customized to the bony anatomy of thepatient.

The cutting block 1010 includes a number of other surgical tool guidebodies 1028. In the illustrative embodiment, each of the tool guidebodies 1028 is a drill guide and fixation guide configured to guide afixation pin into engagement with a patient's bone to couple the cuttingblock 1010 to the bone.

Referring now to FIGS. 40-41, the cutting block 1110 includes a pair ofcutting guide slots 1112, 1114 positioned to guide a customized,patient-specific resection of a distal end of a patient's femur. In theillustrative embodiment, the cutting block 1110 includes a number ofbone-facing surfaces 1116 that have negative contours 38 that areconfigured to receive portions of the patient's bone.

The cutting block 1110 includes a distal resection guide body 1120includes a pair of elongated openings 1122 that are defined in its freeend 1124 and a number of inner walls 1126 that extend inwardly from theopenings 1122. Each opening 1122 and the inner walls 1126 cooperate todefine the cutting guide slots 1112, 1114, which are sized and shaped toguide a surgical tool such as, for example, a cutting blade, intoengagement with the patient's bone. The cutting guide slot 1114 isarranged distally of the cutting guide slot 1112 to offer the surgeonthe option of making a second, pre-planned resection during surgery,thereby providing the surgeon with additional flexibility during surgerywhile at the same time maintaining the benefits of the pre-operativeplanning.

As shown in FIGS. 40-41, the cutting block 1110 includes a number ofother surgical tool guide bodies 1130. In the illustrative embodiment,each of the tool guide bodies 1130 is a drill guide and fixation guideconfigured to guide a fixation pin into engagement with a patient's boneto couple the cutting block 1110 to the bone.

It should be appreciated that in some embodiments the metalliccustomized patient-specific surgical instrument comprises a base platesized to be positioned on a resected surface of a distal end of apatient's femur. The base plate has a bone-facing surface, a distalsurface positioned opposite the bone-facing surface, and an outer wallextending between the bone-facing surface and the distal surface. Themetallic customized patient-specific surgical instrument comprises abody attached to, and extending from, the distal surface to a freedistal end, and the body includes an elongated opening that is definedin its free distal end. A cutting guide slot extends from the opening inthe body through a first opening defined in the bone-facing surface, andthe cutting guide slot is sized to receive a cutting saw blade. A bossis attached to, and extends from, the distal surface to a free distalend spaced apart from the free distal end of the body. The boss includesan opening that is defined in its free distal end. The metalliccustomized patient-specific surgical instrument also comprises a drillguide slot extending from the opening in the boss through a secondopening defined in the bone-facing surface. The drill guide slot issized to receive a surgical drill.

In some embodiments, the bone-facing surface may include a customizedpatient-specific outer edge that is shaped to match an outer edge of theresected surface of the distal end of the patient's femur.

Additionally, in some embodiments, the metallic customizedpatient-specific surgical instrument may include a notch that is definedby a section of the outer edge, and the cutting guide slot may open intothe notch. In some embodiments, the section of the outer edge may be asuperior section such that the notch is defined at a superior end of themetallic customized patient-specific surgical instrument.

In some embodiments, the section of the outer edge may be an inferiorsection such that the notch is defined at an inferior end of themetallic customized patient-specific surgical instrument.

In some embodiments, the body may be a first body, the cutting guide maybe a first cutting guide, and the metallic customized patient-specificsurgical instrument may further comprise a second body attached to, andextending from, the distal surface to a distal end spaced apart from thedistal ends of the first body and the boss. The second body may includean elongated opening that is defined in its distal end. A second cuttingguide slot may extend from the opening in the second body through athird opening defined in the bone-facing surface. The second cuttingguide slot may be sized to receive a cutting saw blade.

In some embodiments, the first cutting guide may define a first cuttingplane, and the second cutting guide may define a second cutting planethat is angled relative to the first cutting plane. Additionally, insome embodiments, the metallic customized patient-specific surgicalinstrument may further comprise a third body attached to, and extendingfrom, the distal surface to a distal end attached to the distal end ofthe second body. The third body may include an elongated opening that isdefined in its distal end. A third cutting guide slot may extend fromthe opening in the third body through a fourth opening defined in thebone-facing surface. The third cutting guide slot may be sized toreceive a cutting saw blade and may intersect the second cutting guideslot.

In some embodiments, the third cutting guide may define a third cuttingplane that is angled relative to the first cutting plane and the secondcutting plane. Additionally, in some embodiments, a passageway may bedefined between a surface of the second body, a surface of the thirdbody, and the distal surface of the base plate.

In some embodiments, the metallic customized patient-specific surgicalinstrument may further comprise a fourth body attached to, and extendingfrom, the distal surface to a free distal end spaced apart from thedistal ends of the first, second, and third bodies. The fourth body mayinclude an elongated opening that is defined in its distal end, and afourth cutting guide slot may extending from the opening in the fourthbody through a fifth opening defined in the bone-facing surface. Thefourth cutting guide slot may be sized to receive a cutting saw bladeand crossing the second cutting guide slot.

In some embodiments, the metallic customized patient-specific surgicalinstrument may include a plurality of laminations of metallic material.

It should also be appreciated that in some embodiments a metalliccustomized patient-specific surgical instrument comprises a base platesized to be positioned on a resected surface of a distal end of apatient's femur. The base plate has a bone-facing surface, a distalsurface positioned opposite the bone-facing surface, and an outer wallextending between the bone-facing surface and the distal surface. Themetallic customized patient-specific surgical instrument also comprisesan anterior resection guide body attached to, and extending from, thedistal surface to a free distal end. The anterior resection guide bodyincludes an anterior cutting guide slot sized to receive a cutting sawblade. A posterior resection guide body is attached to, and extendingfrom, the distal surface to a free distal end, and the posteriorresection guide body includes a posterior cutting guide slot sized toreceive a cutting saw blade. The metallic customized patient-specificsurgical instrument also comprises a pair of chamfer resection guidebodies attached to, and extending from, the distal surface. Each chamferresection guide body includes a chamfer cutting guide slot sized toreceive a cutting saw blade, and each chamfer cutting guide slot extendsobliquely relative to the other cutting guide slots.

In some embodiments, the metallic customized patient-specific surgicalinstrument may further comprise a boss attached to, and extending from,the distal surface to a free distal end spaced apart from the freedistal end of the body. The boss may include an opening that is definedin its free distal end, and a drill guide slot may extend from theopening in the boss through a second opening defined in the bone-facingsurface. The drill guide slot may be sized to receive a surgical drill.

In some embodiments, the bone-facing surface may include a customizedpatient-specific outer edge that is shaped to match an outer edge of theresected surface of the distal end of the patient's femur.

Additionally, in some embodiments, the metallic customizedpatient-specific surgical instrument may include a superior notch thatis defined by a section of the outer edge, and the anterior cuttingguide slot may open into the superior notch.

In some embodiments, the metallic customized patient-specific surgicalinstrument may include an inferior notch that is defined by a section ofthe outer edge, and the posterior cutting guide slot may open into theinferior notch.

In some embodiments, the metallic customized patient-specific surgicalinstrument may include a plurality of laminations of metallic material.

It should also be appreciated that in some embodiments a method ofperforming an orthopaedic surgery comprises aligning a customizedpatient-specific surgical instrument with a resected distal surface of apatient's bone, positioning the customized patient-specific surgicalinstrument in contact with the resected distal surface, and rotating thecustomized patient-specific surgical instrument on the resected distalsurface to align an outer perimeter edge of the resection distal surfacewith a customized, patient-specific outer edge of a bone-facing surfaceof the customized patient-specific surgical instrument, and inserting acutting saw through a cutting guide slot defined in the customizedpatient-specific surgical instrument to resect the patient's bone.

In some embodiments, the customized patient-specific surgical instrumentused in the method includes an anterior cutting guide slot, a posteriorcutting guide slot, and a pair of chamfer cutting guide slots.

It should be appreciated that in some embodiments an orthopaedicsurgical instrument comprising a customized patient-specific surgicalinstrument is disclosed. The customized patient-specific surgicalinstrument comprises a metallic base plate sized to be positioned on apatient's bone. The base plate has a bone-facing surface including acustomized patient-specific negative contour configured to receive acorresponding positive contour of the patient's bone and an outersurface positioned opposite the bone-facing surface. The customizedpatient-specific surgical instrument also comprises a metallic guidebody attached to, and extending from, the outer surface to a free end.The guide body includes an elongated opening that is defined in its freeend. A guide slot extends from the opening in the guide body through afirst opening defined in the bone-facing surface. The guide slot issized and shaped to guide a surgical tool into engagement with thepatient's bone.

In some embodiments, the guide slot may be sized and shaped to guide afixation pin into engagement with the patient's bone. In someembodiments, the guide slot may be sized and shaped to guide a cuttingsaw blade into engagement with the patient's bone.

In some embodiments, the customized patient-specific surgical instrumentmay also comprise a boss attached to, and extending from, the outersurface to a free end spaced apart from the free end of the guide body.The boss may include an opening that is defined in its free end, and adrill guide slot may extend from the opening in the boss through asecond opening defined in the bone-facing surface. The drill guide slotmay be sized and shaped to guide a surgical drill or fixation pin intoengagement with the patient's bone.

In some embodiments, the boss may extend from a base attached to theouter surface of the base plate to the free end. The base may be widerthan the free end, and the boss may include a tapered surface thatextends from the base to the free end.

In some embodiments, the cutting guide slot may extend in ananterior-posterior direction, the drill guide slot may be a first drillguide slot extending in a superior-inferior direction, and thecustomized patient-specific surgical instrument may further comprise asecond drill guide slot extending in an anterior-posterior directionfrom a second opening in the body through a third opening defined in thebone-facing surface. The second drill guide slot may be sized and shapedto guide a surgical drill into engagement with the patient's bone.

In some embodiments, the base plate may include a pair ofposteriorly-extending arms. Each arm may include a portion of thecustomized patient-specific negative contour configured to receive aportion of the corresponding positive contour of the patient's bone.

In some embodiments, the customized patient-specific surgical instrumentmay include a customized patient-specific cavity that is defined in thebase plate. The cavity may be sized and shaped to be positioned over aportion of the patient's bone to prevent contact between the portion ofpatient's bone and the customized patient-specific surgical instrument.Additionally, in some embodiments, the cavity is positioned proximal ofthe guide body.

In some embodiments, the base plate may include a first section attachedto one of a distal end and a proximal end of the guide body, and asecond section that is spaced apart from the first section of the baseplate and is attached to the other of the distal end and the proximalend of the guide body.

In some embodiments, the first section may include a pair ofposteriorly-extending arms. Each arm may include a portion of thecustomized patient-specific negative contour configured to receive aportion of the corresponding positive contour of the patient's bone.Additionally, in some embodiments, the customized patient-specificsurgical instrument may include a plurality of openings extendingthrough the bone-facing and outer surfaces of the posterior-extendingarms of the first section and the bone-facing and outer surfaces of thesecond section of the base plate.

In some embodiments, the customized patient-specific surgical instrumentmay be a single monolithic metallic component including a plurality oflaminations.

It should be appreciated that in some embodiments a customizedpatient-specific surgical instrument comprises a metallic guide bodyextending from a posterior end to a free anterior end. The guide bodyincludes an elongated opening that is defined in its free anterior end.A cutting guide slot extends from the opening in the guide body. Theguide slot is sized and shaped to guide a cutting saw blade intoengagement with a patient's bone. The customized patient-specificsurgical instrument also includes a first plate section extending fromthe posterior end of the metallic guide body, and the first platesection includes a pair of posterior-extending arms. Each arm includes afirst portion of a customized patient-specific negative contourconfigured to receive a first portion of a corresponding positivecontour of the patient's bone. The customized patient-specific surgicalinstrument also includes a second plate section spaced apart from thefirst plate section and extending from the posterior end of the metallicguide body. The second plate section includes a bone-facing surfaceincluding a second portion of the customized patient-specific negativecontour configured to receive a second portion of the correspondingpositive contour of the patient's bone.

In some embodiments, the customized patient-specific surgical instrumentmay also comprise a first boss attached to, and extending from, thesecond plate section to an end spaced apart from the free anterior endof the guide body. The first boss may include an opening that is definedin its end, and a first drill guide slot may extend from the opening inthe first boss. The first drill guide slot may be sized and shaped toguide a surgical drill into engagement with the patient's bone.

In some embodiments, the customized patient-specific surgical instrumentmay further comprise a second boss attached to, and extending from afirst arm of the pair of posterior-extending arms to a free end. thesecond boss may include an opening that is defined in its free end, anda second drill guide slot extending from the opening in the second boss.The second drill guide slot may be sized and shaped to guide a surgicaldrill into engagement with the patient's bone.

In some embodiments, the customized patient-specific surgical instrumentmay further comprise a third boss attached to, and extending from, asecond arm of the pair of posterior-extending arms to a free end. Thethird boss may include an opening that is defined in its free end, and athird drill guide slot extending from the opening in the third boss. Thethird drill guide slot may be sized and shaped to guide a surgical drillinto engagement with the patient's bone.

Additionally, in some embodiments, the customized patient-specificsurgical instrument may be a single monolithic metallic componentincluding a plurality of laminations.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It should be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. A method of manufacturing a customized patient-specific orthopaedicsurgical instrument, the method comprising: generating athree-dimensional model of a patient's bone based on patient-specificdata, identifying a first region of the three-dimensional model of thepatient's bone, defining an outer boundary of a customizedpatient-specific surgical instrument on the three-dimensional model ofthe patient's bone, generating a customized patient-specific surgicalinstrument model within the outer boundary, the customizedpatient-specific surgical instrument model comprising a bone-facingsurface including a customized patient-specific negative contour thatreceives a corresponding positive contour of the patient's bone, andfabricating the customized patient-specific orthopaedic surgicalinstrument from metallic material based on the customizedpatient-specific surgical instrument model, wherein generating thecustomized patient-specific surgical instrument model comprises: (i)defining a cavity in the bone-facing surface over the first region ofthe three-dimensional model of the patient's bone, the cavity having anouter edge aligned with the outer edge of the first region, (ii)generating an outer surface of the customized patient-specific surgicalinstrument opposite the bone-facing surface, (iii) extending a guidebody outward from the outer surface of the customized patient-specificsurgical instrument model to a free end, and (iv) defining a guide slotin the guide body, the guide slot being sized and shaped to guide asurgical tool into engagement with the patient's bone.
 2. The method ofclaim 1, further comprising identifying a planned resection plane on thethree-dimensional model of the patient's bone based on thepatient-specific data, wherein defining the guide slot through the guidebody includes: aligning the guide slot with the planned resection plane,and sizing and shaping the guide slot to guide the cutting saw bladealong the planned resection plane into engagement with the patient'sbone.
 3. The method of claim 2, wherein sizing and shaping the guideslot includes defining the guide slot between a medial sidewall and alateral sidewall of the guide body, and at least one of the medialsidewall and the lateral sidewall are angled relative to the other ofthe medial sidewall and the lateral sidewall.
 4. The method of claim 2,wherein the guide slot is a first guide slot, and generating thecustomized patient-specific surgical instrument model further comprises(i) extending a boss outward from the outer surface of the customizedpatient-specific surgical instrument model to a free end that is spacedapart from the free end of the guide body, and (ii) defining a drillguide slot in the boss.
 5. The method of claim 4, wherein: extending theboss outward from the outer surface includes defining a tapered surfaceon a first side of the boss, and fabricating the customizedpatient-specific orthopaedic surgical instrument from metallic materialincludes layering metallic material in a fabrication machine such thatthe tapered surface faces downward in the fabrication machine.
 6. Themethod of claim 1, wherein generating the customized patient-specificsurgical instrument model further comprises defining a plurality ofapertures that extend through the outer surface and the bone-facingsurface.
 7. The method of claim 6, wherein generating the customizedpatient-specific surgical instrument model further comprises defining asecond plurality of apertures through the guide body of the customizedpatient-specific surgical instrument model.
 8. The method of claim 7,wherein each of the apertures includes a diamond-shaped opening.
 9. Themethod of claim 1, wherein: extending the guide body outward from theouter surface of the customized patient-specific surgical instrumentmodel to the free end includes defining a tapered surface on a firstside of the guide body, and fabricating the customized patient-specificorthopaedic surgical instrument from metallic material includes layeringmetallic material in a fabrication machine such that the tapered surfacefaces downward in the fabrication machine.
 10. The method of claim 1,wherein fabricating the customized patient-specific orthopaedic surgicalinstrument from metallic material based on the customizedpatient-specific surgical instrument model includes forming thecustomized patient-specific orthopaedic surgical instrument as a singlemonolithic component.
 11. The method of claim 10, wherein the singlemonolithic component includes a plurality of laminations of metallicmaterial.
 12. A method of manufacturing a customized patient-specificorthopaedic surgical instrument, the method comprising: generating athree-dimensional model of a patient's bone based on patient-specificdata, defining an outer boundary of a customized patient-specificsurgical instrument on the three-dimensional model of the patient'sbone, generating a customized patient-specific surgical instrument modelwithin the outer boundary, the customized patient-specific surgicalinstrument model including a customized patient-specific bone facingsurface, and fabricating the customized patient-specific orthopaedicsurgical instrument from metallic material based on the customizedpatient-specific surgical instrument model, wherein generating thecustomized patient-specific surgical instrument model comprises: (i)generating an outer surface of the customized patient-specific surgicalinstrument opposite the bone-facing surface, (ii) extending a guide bodyoutward from the outer surface of the customized patient-specificsurgical instrument model to a free end, and (iii) defining a guide slotin the guide body, the guide slot being sized and shaped to guide asurgical tool into engagement with the patient's bone.
 13. The method ofclaim 12, further comprising planning a resected surface of thepatient's bone, wherein generating the customized patient-specificsurgical instrument model includes shaping an outer edge of thebone-facing surface to match an outer edge of the planned resectedsurface of the patient's bone.
 14. The method of claim 12, wherein theguide body is a first guide body, and generating the customizedpatient-specific surgical instrument model further comprises extending asecond guide body outward from the outer surface of the customizedpatient-specific surgical instrument model to an end spaced apart fromthe free end of the first guide body, defining a second guide slot inthe second guide body, the second guide slot being sized and shaped toguide a surgical tool into engagement with the patient's bone andextending transverse to the first guide slot.
 15. The method of claim12, wherein generating the customized patient-specific surgicalinstrument model further comprises: extending a third guide body outwardfrom the outer surface of the customized patient-specific surgicalinstrument model to a free end spaced apart from the first guide body,and defining a third guide slot the second guide slot being sized andshaped to guide a surgical tool into engagement with the patient's boneand intersecting the second cutting guide slot.
 16. The method of claim14, wherein the second guide body includes a boss having a tapered outersurface, and the second guide slot is a drill guide slot sized andshaped to guide a surgical drill into engagement with the patient'sbone.
 17. The method of claim 12, wherein fabricating the customizedpatient-specific orthopaedic surgical instrument from metallic materialbased on the customized patient-specific surgical instrument modelincludes forming the customized patient-specific orthopaedic surgicalinstrument as a single monolithic component.
 18. The method of claim 17,wherein the single monolithic component includes a plurality oflaminations of metallic material.
 19. The method of claim 17, whereinfabricating the customized patient-specific orthopaedic surgicalinstrument includes operating a three-dimensional metal printer tofabricate the customized patient-specific surgical instrument by forminglaminations of metallic material.
 20. A method of designing a customizedpatient-specific orthopaedic surgical instrument, the method comprising:generating a three-dimensional model of a patient's bone based onpatient-specific data, defining an outer boundary of a customizedpatient-specific surgical instrument on the three-dimensional model ofthe patient's bone, and generating a customized patient-specificsurgical instrument model within the outer boundary, the customizedpatient-specific surgical instrument model including a customizedpatient-specific bone facing surface, wherein generating the customizedpatient-specific surgical instrument model comprises: (i) generating anouter surface of the customized patient-specific surgical instrumentopposite the bone-facing surface, (ii) extending a guide body outwardfrom the outer surface of the customized patient-specific surgicalinstrument model to a free end, and (iii) defining a guide slot in theguide body, the guide slot being sized and shaped to guide a surgicaltool into engagement with the patient's bone.